I want to take a lead from a comment posted by Chris on the comments page for podcast #12:
In convincing Lee to abandon his father[Dualla] removes a central leader and a huge cadre of warriors in the death of New-Caprica. Leaving a fattened and weakened Lee to lead a civilian contingent.
There’s room for gobs of speculation about anyone on the show being a Cylon, but this Dee-as-a-Cylon thing really interests me. Maybe it’s my unfettered grief for Billy and latent irritation at Dee for dumping him. But if Dee was trying to get Billy out of the way to hook up with someone higher up, Lee would be the best choice. And, as Chris says, Lee got fat only after he started hanging out with Dee. She leaves bowls of walnuts lying around for him, encouraging him to snack, and probably hid his jumprope too. If poor Fat Lee got sidetracked by the snacks in the middle of an attack, he very well could lead the humans to doom. Plus Dee’s always been right there in CIC with the highest-ranking officials, and she always knows what’s going on.
Also, and as a secure woman, I think I can say this- Dee is pretty hot, which ultimately puts her high on the list for female Cylon territory. Just my opinion.